[EABI] Add LLVM support for -meabi flag

"GCC requires the freestanding environment provide memcpy, memmove, memset
and memcmp": https://gcc.gnu.org/onlinedocs/gcc-5.2.0/gcc/Standards.html

Hence in GNUEABI targets LLVM should not convert 'memops' to their equivalent
'__aeabi_memops'. This convertion violates GCC contract.

The -meabi flag controls whether or not LLVM will modify 'memops' in GNUEABI
targets.

Without -meabi: use the triple default EABI.
With -meabi=default: use the triple default EABI.
With -meabi=gnu: use 'memops'.
With -meabi=4 or -meabi=5: use '__aeabi_memops'.
With -meabi set to an unknown value: same as -meabi=default.

Patch by Vinicius Tinti.

llvm-svn: 252462

1 files changed, 9 insertions, 0 deletions

diff --git a/llvm/lib/Target/ARM/ARMTargetMachine.cpp b/llvm/lib/Target/ARM/ARMTargetMachine.cpp
index 9a5efc8..fca1901 100644
--- a/llvm/lib/Target/ARM/ARMTargetMachine.cpp
+++ b/llvm/lib/Target/ARM/ARMTargetMachine.cpp
@@ -188,6 +188,15 @@ ARMBaseTargetMachine::ARMBaseTargetMachine(const Target &T, const Triple &TT,
   if (Options.FloatABIType == FloatABI::Default)
     this->Options.FloatABIType =
         Subtarget.isTargetHardFloat() ? FloatABI::Hard : FloatABI::Soft;
+
+  // Default to triple-appropriate EABI
+  if (Options.EABIVersion == EABI::Default ||
+      Options.EABIVersion == EABI::Unknown) {
+    if (Subtarget.isTargetGNUAEABI())
+      this->Options.EABIVersion = EABI::GNU;
+    else
+      this->Options.EABIVersion = EABI::EABI5;
+  }
 }
 
 ARMBaseTargetMachine::~ARMBaseTargetMachine() {}